1. Field of the Invention
The present invention relates to digital valves, and, more particularly, to a simple valve construction which can be manufactured to provide a precise flow control.
2. Description of the Prior Art
In present day process control systems involving the control of fluid, digital computers play an ever increasing part in automating the control of the fluid flow. Recent developments in microcomputer technology have simplified the automatic control of elements, such as valves. Since the computer output signal is digital in nature, any valve which can respond directly to digital signals is greatly preferred over conventional valves in the precision automatic control of fluid.
Many United States patents disclose digital valves, such as U.S. Pat. Nos. 3,063,468; 3,072,146; 3,331,393; 3,746,041; 3,785,389; 3,905,394; 3,937,248; and 3,942,553. These patents, and other patents noted hereinafter, disclose specific features of valves which are desirable for a simple, automatic controlled, digital valve. For example, several valve patents, including U.S. Pat. Nos. 2,790,680; 3,063,468; 3,072,146; 3,343,566; 3,349,798; and 3,746,041 disclose a rectangular slot, or slots, for the control of fluid flow. U.S. Pat. No. 3,331,393 discloses a valve body having an inlet passage with an outlet passage on either side thereof, and some digital valve patents (U.S. Pat. Nos. 3,785,389 and 3,905,394) disclose a computer controlled digital valve with a sensor providing signals to the computer.